Battery cell and manufacturing method thereof
The battery cell design with notched inactive portions and load-bearing current collectors addresses the challenges of tab attachment in cylindrical cells, enabling faster production and enhanced conductivity.
Patent Information
- Application Number
- JP2025554339
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-05
- Filing Date
- 2023-12-05
- Publication Date
- 2025-11-27
AI Technical Summary
The manufacturing of cylindrical battery cells is hindered by the time-consuming process of attaching current collecting tabs, which can lead to poor attachment, increased production time, and potential short circuits due to the complexity and fragility of the tabs.
A battery cell design featuring a first and second electrode sheet with inactive portions and notches for forming bendable current collecting tabs, along with load-bearing portions on current collectors to hold the tabs in position, allowing for reduced cuts and easier bending, thus improving production speed and reducing scrap rates.
The new design enables efficient manufacturing at industrial speeds with improved conductivity and reduced scrap rates by minimizing cuts and simplifying the tab attachment process, while avoiding short circuits.
Smart Images
Figure 2025538318000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to the field of electric batteries for electric vehicles. In particular, the present invention relates to battery cells. More particularly, the present invention relates to cylindrical cells. [Background technology]
[0002] Cylindrical battery cells are becoming increasingly used in the automotive industry.
[0003] The advantage of cylindrical cells is that they can store a large amount of energy in a small volume, so for a given energy storage capacity they take up less space in the car.
[0004] The energy storage capacity of a cylindrical cell depends on its diameter: the larger the diameter of the cylindrical cell, the greater the energy storage capacity.
[0005] The cylindrical cell has at least: Positive electrode sheet Insulation separator sheet Negative electrode sheet Insulation separator sheet The laminate is wound around a mandrel.
[0006] Current collecting tabs are added along the electrode sheets and attached to the positive and negative electrode sheets. Although automated, this process is particularly time-consuming and slows down the manufacturing rate of cylindrical cells. Furthermore, poor attachment and / or contact between the tabs and the electrodes can reduce the performance of the cylindrical cell or even cause a short circuit.
[0007] To overcome these problems, some manufacturers have proposed eliminating the retrofit tab attachment method.
[0008] One such solution involves cutting cuts directly into the electrode sheet to form current collecting tabs before winding it onto a rotating mandrel, and then bending these tabs to contact additional current collectors after winding.
[0009] The drawback of this method is that it requires multiple slits to be made during the cutting process before winding onto the mandrel, which results in a slower cell production rate due to the large number of slits required.
[0010] Another drawback to this method is that the current collecting tabs can be damaged while being wound onto the mandrel because the current collecting tabs are thin and easily damaged during handling.
[0011] Another drawback of this method is that the number of tabs is large and they are difficult to bend. Furthermore, the process of attaching the tabs in a curved state is time-consuming and technically difficult to achieve at industrial production speeds.
[0012] Therefore, an object of the present invention is to solve the above problems. Summary of the Invention [Means for solving the problem]
[0013] To this end, the present invention first provides a battery cell for an electric vehicle, the battery cell comprising: a first electrode sheet having a first active portion coated with an active material and a first inactive portion; a first insulating separator sheet; a second electrode sheet having a second active portion coated with an active material and a second inactive portion; a second insulating separator sheet; At least one continuous laminate consisting of at least one laminate is wound on itself about a central axis to form a cylinder, the cell having a first end from which a first inactive portion protrudes, the first inactive portion having at least two notches between which a bendable current collecting tab is formed, the cell having a first current collector having an inner surface disposed facing the electrode and an outer surface opposite the inner surface, the current collector having at least a first load bearing portion protruding from the inner surface along the central axis, the first load bearing portion configured to contact the current collecting tab and hold the bendable current collecting tab in a bent position; the load bearing portion extends over a length between a proximal end located on the same side as the central axis and a distal end located on the opposite side of the proximal end and on the peripheral edge of the first current collector, the length being measured along a radial axis that passes through the load bearing portion and intersects the central axis and is substantially perpendicular to the central axis; The load bearing portion has a height measured along the central axis from the inner surface to the contact surface, the height decreasing along the length from the periphery toward the central axis.
[0014] The production of such cells can be carried out at industrial speeds, as the number of cuts is reduced, maintaining acceptable conductivity without compromising cell efficiency. The fewer current collector tabs required compared to current cells, the easier the bending process. As a result, the reject rate is significantly reduced. Furthermore, the unique shape of the load-bearing part allows the current collector tabs to bend along their central axis, so that the tabs can be easily bent in the correct direction simply by placing the current collector. In other words, there is no need to perform a pre-bending process on the current collector tabs (using additional tools, for example, before placing the current collector). This also avoids the formation of random clumps of metal in the area of the current collector tabs.
[0015] Various additional features may be provided, either alone or in combination: The cell has a second end opposite the first end along the central axis, with a second inactive portion protruding from the second end, the second inactive portion having at least two notches forming current collecting tabs therebetween, and the cell has a second current collector having at least a second load bearing portion configured to contact the bendable current collecting tabs and hold them in a bent position. The current collecting tabs are folded towards each other from the periphery of the cell towards the central axis. At least a first load-bearing portion of the first current collector is fixed to a current collecting tab of the first electrode, and at least a second load-bearing portion of the second current collector is fixed to a current collecting tab of the second electrode. Further comprising a plurality of distinct bendable current collecting tab portions at each end, the first and second current collectors comprising a plurality of distinct load bearing portions each configured to contact a current collecting tab portion to hold the current collecting tab in a bent position. The current collector is a metal disk having an inner surface facing the electrode and an outer surface opposite the inner surface, and the cell has at least one load-bearing portion protruding from the inner surface along the central axis. The notch extends over a length approximately equal to the length of the load-bearing part. The inner surface is positioned at a distance from the electrode. The second current collector is substantially identical to the first current collector.
[0016] Second, the present invention provides a battery including a plurality of cells as described above and a connector for connecting the cells to each other.
[0017] Third, the present invention provides a method for manufacturing such a cell, the method comprising the steps of: providing a sheet of a first electrode having a first active portion and a first inactive portion; providing a first insulating separator sheet; providing a sheet of a second electrode having a second active portion and a second inactive portion; providing a sheet of a second insulating separator; sequentially stacking the first electrode, the first insulating separator, the second electrode, and the second insulating separator to form a stack such that the first electrode and the second electrode are laterally offset relative to one another and such that the first inactive portion and the second inactive portion at least partially protrude from the stack; rolling the laminate to form a generally cylindrical shape having a first end with a first inactive portion projecting beyond the laminate and a second end with a second inactive portion projecting beyond the laminate; After the winding step, cutting the first inactive portion and the second inactive portion to form current collecting tabs; positioning a first current collector and a second current collector on the first end and the second end, respectively, such that at least one load bearing portion contacts the at least one current collecting tab portion, thereby bending the current collecting tab; Includes:
[0018] The method further includes welding the load bearing portion of the current collector to the current collecting tab.
[0019] Further features and advantages of the present invention will become apparent from the following detailed description. For an understanding of the present invention, reference is made to the accompanying drawings, in which: [Brief explanation of the drawings]
[0020] [Figure 1] FIG. 1 is a schematic cross-sectional view of a portion of a cylindrical cell according to the present invention. [Figure 2] FIG. 2 is a schematic top view of a current collector according to the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view of the current collector shown in FIG. [Figure 4] FIG. 4 is a schematic diagram of a current collector according to the present invention as viewed from above. [Figure 5] FIG. 5 is a schematic cross-sectional view of the current collector shown in FIG. [Figure 6]FIG. 6 is a schematic diagram of one end of a cell according to the present invention. [Figure 7] FIG. 7 is a schematic diagram of another end of a cell according to the invention. DETAILED DESCRIPTION OF THE INVENTION
[0021] FIG. 1 shows a battery cell 1. The cell 1 is intended to supply power to an electric vehicle. Sheet of first electrode 2 First insulating separator 3 sheet Sheet of second electrode 4 A sheet of second insulating separator 5 The laminate comprises at least one continuous laminate consisting of:
[0022] The laminate is wound on itself around a central axis 8 to form a cylinder.
[0023] The first electrode 2 comprises a first active portion 9 that is coated with an active material and a first inactive portion 10 that is not coated with any active material, and is therefore a metal such as aluminum or copper.
[0024] The second electrode 4 comprises a second active portion 11 coated with an active material and a second inactive portion 12 not coated with any active material, and is therefore a metal such as aluminum or copper.
[0025] The cell 1 has a first end 13. A first inactive portion 10 protrudes from the first end 13. By "protruding" it is meant that the first inactive portion 10 extends along the central axis 8 at least partially beyond the separators 3, 5.
[0026] 6 and 7, the first inactive portion 10 includes at least two notches 14. In the embodiment shown in the drawings, the first inactive portion 10 includes eight notches 14 forming four first tab portions 15. The notches 14 allow for the formation of bendable current collecting tabs 16.
[0027] The cell 1 includes a first current collector 17. The first current collector 17 includes at least a first load bearing portion 18. The first load bearing portion 18 is configured to contact the bendable current collecting tabs 16 and hold them in a bent position.
[0028] Manufacturing of such cells 1 can be done at industrial speeds because the number of cuts 14 is reduced, maintaining acceptable conductivity without compromising the efficiency of the cells 1. The fewer current collector tabs 16 compared to current cells also facilitates bending, resulting in significantly lower scrap rates.
[0029] Advantageously, the cell 1 has a second end 19 located opposite the first end 13 along the central axis 8. A second inert portion 12 projects from the second end 19. By "projecting" it is meant that the second inert portion 12 extends beyond the separators 3, 5 along the central axis 8.
[0030] Advantageously, the second inactive portion 12 comprises at least two cut portions 14 between which the current collecting tabs 16 are formed. In the embodiment shown in the drawings, the second inactive portion 12 comprises eight cut portions 14 forming four second tab portions 32.
[0031] Advantageously, the cell 1 comprises a second current collector 20 having at least a second load bearing portion 21 configured to contact the bendable current collecting tabs 16 and hold them in a bent position.
[0032] Advantageously, the second end 19 is identical to the first end 13 for manufacturing uniformity, which simplifies the manufacturing method of the cell 1.
[0033] Advantageously, the current collecting tabs 16 are folded towards each other as can be seen in Figure 1. The current collecting tabs are folded from the periphery 22 of the cell 1 towards the central axis 8.
[0034] The current collecting tabs 16 are bent in this direction, which is advantageous in avoiding the risk of short circuits.
[0035] Advantageously, the first load bearing portion 18 of the first current collector 17 is fixed to the current collecting tab 16 of the first electrode 2. Advantageously, the second load bearing portion 21 of the second current collector 20 is fixed to the current collecting tab 16 of the second electrode 4, for example by welding.
[0036] By fastening only the load bearing portions 18, 21 to the current collecting tab 16, the number of welds can be reduced while maintaining acceptable electrical conductivity, thereby increasing production speed.
[0037] Advantageously, the first current collector 17 comprises four distinct first load bearing portions 18. Each of the first load bearing portions 18 is configured to contact a first current collecting tab portion 15 and hold the current collecting tab 16 in a folded position.
[0038] Advantageously, the second current collector 20 comprises four different second load bearing portions 21. Each of the second load bearing portions 21 is configured to contact a second current collecting tab portion 32 and to hold the current collecting tab 16 in a folded position.
[0039] Advantageously, the first and second current collectors 17, 20 have the shape of metal disks having an inner surface 23 arranged facing the electrodes 2, 4 and an outer surface 24 opposite the inner surface 23. The load-bearing portions 18, 21 protrude from the inner surface 23 along the central axis 8.
[0040] Such load support portions 18, 21 ensure contact with the current collecting tab 16.
[0041] Advantageously, the first current collector 17 and the second current collector 20 are substantially identical.
[0042] Advantageously, each load-bearing portion 18, 21 extends over a length L. The length L is measured along a radial axis 25 through the load-bearing portion 18, 21. The radial axis 25 is substantially perpendicular to the central axis 8 and intersects with the central axis 8. The length L is measured between a proximal end 26 located on the same side as the central axis 8 and a distal end 27 located on the opposite side of the proximal end 26 along the radial axis 25, which is substantially perpendicular to the central axis 8. The distal end 27 is located on the same side as the peripheral edge 22 of the cell 1. The cut-out portion 14 extends over a length substantially equal to the length L.
[0043] There are as many radial axes 25 as there are load bearing portions 18, 21. In this case, each bearing portion 18, 21 is associated with a radial axis 25 that passes through the load bearing portion 18, 21, is substantially perpendicular to the central axis 8, and intersects with the central axis 8.
[0044] The lengths of the load bearing portions 18, 21 and the notch 14 are approximately equal to optimize contact and maintain acceptable electrical conductivity.
[0045] Advantageously, two adjacent notches are spaced apart by a distance D1 which is less than or equal to 80% of the inner diameter D2, which corresponds to the outer diameter of the winding mandrel.
[0046] By setting the distance D1 in this manner, the current collecting tab 16 can be easily bent.
[0047] Advantageously, the load bearing portions 18 , 21 of the current collectors are provided with contact surfaces 28 configured to come into contact with the current collecting tabs 16 .
[0048] This allows optimum conductivity to be maintained.
[0049] Advantageously, the load bearing portions 18, 21 have a height H measured in a direction parallel to the central axis 8. The height H is measured from the inner surface 23 of the load bearing portion to the contact surface 28. The height H decreases along the length L from the periphery 22 of the cell 1 towards the central axis 8.
[0050] This ensures that the current collecting tab 16 is bent in the direction of the central axis 8, and the bending in the correct direction can be easily achieved by simply positioning the current collectors 17, 20. In other words, there is no need to perform a pre-bending step on the current collecting tab (before placing the current collector using an additional tool, etc.). Also, random clumping of metal in the area of the current collecting tab is avoided.
[0051] Advantageously, the inner surfaces 23 of the first current collector 17 and the second current collector 20 are located at a distance from the first electrode 2 and the second electrode 4, respectively, so that there is no contact between the inner surfaces 23 and the inactive parts of the electrodes.
[0052] Advantageously, the first tab portions 15 are arranged at 90° to one another, so that the first tab portions 15 form an angle α of 90° to one another.
[0053] Advantageously, the second tab portions 32 are arranged at 90° to one another, so that the second tab portions 32 form an angle α of 90° to one another.
[0054] This reduces the distance electrons have to travel through the electrode sheets, improving conductivity and therefore cell performance.
[0055] As shown in FIG. 1, the cell is assembled by inserting the assembly of the wound stack and current collector into a rigid cylindrical capsule 29. The negative second current collector 20 is in contact with the cylindrical capsule 29, resulting in a negative bias. Conversely, the first current collector 17 is positively biased and is not in direct contact with the cylindrical capsule 29. The cell 1 includes a cover 30, which is additionally attached to the first current collector 17 and therefore positively biased. As shown in FIG. 1, an insulating element 31 is disposed between the first current collector 17 and the cylindrical capsule 29. A further insulating element 31 is disposed between the cover 30 and the cylindrical capsule 29. These insulating elements 31 prevent short circuits.
[0056] The present invention also relates to a battery cell (not shown) made up of a plurality of cells 1. The battery is provided with connectors for connecting the cells to each other.
[0057] The method for manufacturing the cell will be described below.
[0058] This method is A first electrode sheet having a first active portion and a first inactive portion. First insulating separator sheet A sheet of a second electrode having a second active portion and a second inactive portion. Second separator sheet providing a
[0059] The method includes sequentially stacking a first electrode, a first insulating separator, a second electrode, and a second insulating separator. At the first end, a first inactive portion protrudes beyond the laminate. At the second end, a second inactive portion protrudes beyond the laminate. This is how it is done.
[0060] The method includes rolling the laminate onto itself to form substantially a cylinder such that at a first end of the cylinder, a first inert portion protrudes from the laminate and at a second end of the cylinder, a second inert portion protrudes from the laminate.
[0061] Following the winding step, the method includes a cutting step in which cuts are made to form current collecting tabs. In the embodiment shown in the drawings, eight cuts are made to form four current collecting tab portions at each end of the cell.
[0062] The method includes placing a first current collector on the first end and a second current collector on the second end such that each load-bearing portion contacts a current collecting tab portion, causing the current collecting tab to tilt toward the central axis.
[0063] Such cells can be manufactured at industrial speeds without compromising cell efficiency, due to the more rational number of notches. Furthermore, the notches are made after winding, not before, which prevents damage to the current collector tabs. The number of current collector tabs is also reduced compared to current cells, making bending easier. As a result, scrap rates are significantly lower.
[0064] Advantageously, the method includes the step of welding the load bearing portion to the current collecting tab, thereby securing the current collector to the current collecting tab.
Claims
1. A battery cell (1) for an electric vehicle, the battery cell (1) comprising: a sheet of a first electrode (2) comprising a first active part (9) coated with an active material and a first inactive part (10); a sheet of a first insulating separator (3); a sheet of a second electrode (4) comprising a second active part (11) coated with an active material and a second inactive part (12); a sheet of second insulating separator (5); At least one continuous laminate consisting of the at least one laminate is wound on itself around a central axis (8) to form a cylinder, the cell (1) having a first end (13) from which the first inactive portion (10) protrudes, the first inactive portion (10) in the cell (1) having at least two notches (14) between which a bendable current collecting tab (16) is formed, the cell having a first current collector (17) having an inner surface (23) arranged facing an electrode and an outer surface (24) located opposite the inner surface (23), the current collector having at least a first load-bearing portion (18) protruding from the inner surface (23) along the central axis (8), the first load-bearing portion (18) being configured to contact the current collecting tab (16) and hold the bendable current collecting tab (16) in a bent position; the load-bearing portion (18) extends over a length (L) between a proximal end (26) located on the same side as the central axis (8) and a distal end (27) located on the opposite side of the proximal end (26) and on the peripheral edge (22) side of the first current collector (17), the length (L) being measured along a radial axis (25) that passes through the load-bearing portion (18), intersects the central axis (8), and is substantially perpendicular to the central axis (8); The load-bearing portion (18) has a height (H) measured along the central axis (8) from the inner surface (23) to the contact surface (28), the height (H) decreasing along the length (L) from the periphery (22) towards the central axis (8). A cell (1).
2. The cell (1) has a second end (19) located opposite the first end (13) along the central axis (8), from which the second inactive portion (12) projects; In the cell (1), the second inactive portion (12) has at least two notches (14) forming current collecting tabs (16) between the notches (14); The cell (1) comprises a second current collector (20), the second current collector (20) comprising at least a second load bearing portion (21) configured to contact the bendable current collecting tabs (16) and hold them in a bent position. A cell (1) according to claim 1, characterized in that
3. The current collecting tabs (16) are folded toward each other from the peripheral edge (22) of the cell (1) toward the central axis (8). A cell (1) according to claim 1 or 2, characterized in that
4. At least the first load-bearing portion (18) of the first current collector (17) is fixed to the current collecting tab (16) of the first electrode (2), and at least the second load-bearing portion (21) of the second current collector (20) is fixed to the current collecting tab (16) of the second electrode (4). A cell (1) according to claim 2 or claim 3 in combination with claim 2, characterized in that
5. Further comprising a plurality of bendable current collecting tab portions (15, 32) at each end (13, 19), which are different from one another; The first and second current collectors (17, 20) comprise a plurality of load-bearing portions (18, 21) that are different from each other, and each of the load-bearing portions (18, 21) is configured to contact the current collecting tab portion (15, 32) to hold the current collecting tab (16) in a folded position.
5. Cell (1) according to claim 4, characterized in that
6. the current collectors (17, 20) are metal disks having an inner surface (23) facing the electrodes (2, 3) and an outer surface (24) located opposite the inner surface (23), and in the cell (1), at least one of the load-bearing portions (18, 21) protrudes from the inner surface (23) along the central axis (8); A cell (1) according to claim 4 or 5, characterized in that
7. The notch (14) extends over a length substantially equal to the length (L).
7. Cell (1) according to claim 6, characterized in that
8. The inner surface (23) is arranged at a distance from the electrodes (2, 4). Cell (1) according to claim 6 or 7, characterized in that
9. The second current collector (20) is substantially identical to the first current collector (17). A cell (1) according to claim 2 or any one of claims 3 to 8 in combination with claim 2, characterized in that
10. A battery comprising a plurality of cells (1) according to any one of claims 1 to 9 and a connector for connecting said cells to one another.
11. A method for manufacturing a cell according to any one of claims 1 to 9, comprising the steps of: providing a sheet of a first electrode having a first active portion and a first inactive portion; providing a sheet of a first insulating separator; providing a sheet of a second electrode having a second active portion and a second inactive portion; providing a sheet of a second insulating separator; sequentially stacking the first electrode, the first insulating separator, the second electrode, and the second insulating separator to form a stack such that the first electrode and the second electrode are laterally offset relative to one another and such that the first inactive portion and the second inactive portion at least partially protrude from the stack; rolling the stack to form a generally cylindrical shape having a first end that causes the first inactive portion to protrude beyond the stack and a second end that causes the second inactive portion to protrude beyond the stack; after the winding step, cutting the first inactive portion and the second inactive portion to form current collecting tabs; disposing a first current collector and a second current collector on the first end and the second end, respectively, such that at least one load bearing portion contacts at least one current collecting tab portion, thereby bending the current collecting tab; Including, A method characterized by:
12. further comprising the step of welding the load-bearing portion of the current collector to the current collecting tab.
12. The method according to claim 11 .
Citation Information
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